1. Field of the Invention
The present invention relates to integrated circuits having sections designed for performing specific dedicated processing functions and other sections designed for performing multiple different processing functions in accordance with various input instructions, and in particular, to such integrated circuits as implemented with electrically programmable logic devices (PLDs).
2. Description of the Related Art
Digital electronic systems often include dedicated hardware in combination with a central processor unit (CPU) and software to achieve the desired data processing, as represented in FIG. 1. The two general types of implementation methods can be characterized as follows: hardware implementations which are fast but difficult to modify, as well as expensive; and software implementations which are slower but simpler to modify, as well as significantly less expensive.
Many circuit designers tend to use the CPU more often because it offers less expensive yet more flexible alternatives for implementing various processing functions. However, an important goal in designing such systems is that of the efficient division of the processing tasks between hardware-based and software-based solutions. Such division of processing tasks must be done early in the design process since modifying the implementation later will be difficult and expensive, and further, will often require that additional hardware be added to an existing circuit board design which already contains the original system.
Accordingly, it would be desirable to have a digital electronic system in which the hardware-based and software-based processing functions can be more quickly and easily, and, therefore, more economically, modified in accordance with the particular application.